Both open and endoscopic surgical procedures often require sutures to ligate, join or otherwise treat tissue. Generally, suture needles with attached suture strands are grasped either manually or by forceps and passed through the desired work site so a knot can be tied. While the procedures are fairly uncomplicated in open surgery where most suture sites are readily accessible, in endoscopic procedures, where access to the work site is not readily available, the surgeon must use auxiliary devices to be able to grasp the suture strands and pass them through desired tissue.
Various instruments and techniques have been developed for surgical repairs requiring the passing of sutures to distant locations. For example, one device for advancing suture directly to a work site is described in U.S. Pat. No. 4,890,615 (Caspari et al.), according to which a suture strand is advanced using a roller mechanism to feed the suture through a hollow needle at the end of an elongated tube into the tissue to be sutured. While suitable for mono-filament suture, such roller-type devices may unravel and disentangle multi-stranded suture which is desirable for certain applications.
In addition, since the work site is typically accessible through a small portal or cannula, it is difficult for the surgeon to pass suture through selected tissue and to form a surgical knot into position adjacent the desired tissue to be sutured. Formation of the knot requires the surgeon to manually tie a knot on the suture strands after the suture is threaded through the tissue to be sutured. The suture must be flexible enough to be manipulated and tied by the surgeon, while also being sufficiently stiff to be directed into the desired position. The knot tying operation is often tedious because, while surgical sutures are often coated to improve tactile smoothness, the coated suture reduces the knot integrity. As a result of these setbacks, there is a need for a multi-stranded suture which can be easily advanced through a cannulated surgical instrument to and from a work site.